Abstract: A lock assembly is provided with a key-activated removable core structure. The lock assembly includes a housing having a first internal compartment disposed at a front end thereof, a second internal compartment disposed at a rear end thereof, and a partition with an aperture and a radial slot therethrough for segregating the first and second internal compartments. The removable core structure is selectively removably disposed within the first internal compartment of the housing and a cam actuation assembly is captively rotatably disposed within the second internal compartment of the housing. The removable core structure includes an exterior shell portion and a key-activated lock plug assembly with a distal driver portion rotatably disposed within the shell portion for rotation between distinct operating positions.